Immunocompromised hosts, including those patients with either AIDS or cancer, are predisposed to infections caused by both bacteria and fungi. The most common fungal infections are caused by yeast such as Candida, Torulopsis or Cryptococcus. Although these organisms grow well on simple media such as blood, chocolate, or Sabouraud's agars, these media do not permit easy recognition of when a mixture of two or three different yeast may be present. Colony morphologies on these agars also cannot be readily used to suggest which species of yeast may be present. In order to facilitate isolation and identification of yeast from patient specimens, we developed a medium which yields good growth of yeast but which also helps differentiate the different species of yeast on the basis of colony morphology and color, The new medium will be evaluated in a comparison with Sabouraud's agar as a primary planting medium for fungal cultures. In addition, the medium will be used as an additional routine blood culture medium in order to enhance the detection of yeast in blood.